Interference eliminator



Dec. 26, 1933. J. WELLS 7 1,941,424

INTERFERENCE ELIMINATOR Filed April 22, 1951 A [mentor far/le s G. WeZLS5 M.

Patented Dec. 26, 1933 UNITED STATES 1,941,424 7 INTERFERENCE ELIMINATORJames G. Wells, Chicago, Ill., assignor to G-M Laboratories, Inc.,Chicago, Ill., a corporation of Illinois Application April 22, 1931.Serial No. 531,951

5 Claims.

My invention relates to a device for suppressing radio radiations from.an oscillating apparatus and more particularly for suppressing or absorbing disturbances emanating from a neon sign.

Neon signs are frequently used in establishments where radio receivingsets are displayed for sale and it has been found that. in many casesthe operation of the sign interferes seriously with the operation ofradio sets in the vicinity of the sign.

An object of the invention is to provide a method and device forsuppressing radio emanations from a device which generates radiantenergy.

A further object is to provide a device for suppressing radio emanationsof a neon sign.

Other objects and advantages will appear as the description proceeds.

The single figure of the drawing illustrates schematically an embodimentof the invention. The drawing illustrates a gaseous discharge tube suchas a neon tube formed into the letters "G-M. This tube is energized bymeans of a constant current transformer 4, the terminals of thesecondary winding of which are connected to electrodes 5 in the ends ofthe tube.

When such tubeis used in a sign, there is set up an oscillation, thefrequency of which is determined by the length and configuration of theglass tubingforming the casing for the gas. This frequency is alsoeffected by the capacity of the tube to ground and the degree ofionization of the gas in the tube. The tube therefore radiates a dampedwave modulated by the supply source frequency that will set up adisturbing interference to nearby radio systems.

It has been found that the radiant energy emanating from the tube may besuppressed by placing an elongated or looped conductor in the vicinityof the tube. When the impedance of the loop is equal to the impedance ofthe circuit setting up the oscillations, the absorption of the energyradiated from the tube will be a maximum. By designing this loop tolengths suitable for the particular length and configuration of the tubeand attaching the ends of the conductor to the tube, it has been foundthat the objectionable radiation from the tube may be suppressed.

In practicing the invention I take a conductor 6, having clips '7attached to its ends and secure one end of the conductor approximately afoot from one end of the tube. The position of the other end of theconductor is then determined by the experiment, attaching it to variouspoints of thetube adjacent the opposite end of the tube until the pointis found at which the interference is no longer noticeable. If theposition of the two ends of the conductor held by-the clips does notresult in the elimination of the disturbance, I change the length ofwire and repeat the experisuppress radiations therefrom.

It will be understood that the nature and embodiment of the inventionherein described and illustrated is merely a convenient and useful formof the invention and many changes and modifications may be made thereinwithout departing from the spirit and scope of the invention.

What I claim as new and desire to protect by Letters Patent of theUnited States is:-

1. In combination with a gaseous discharge tube'a long conductorattached to said tube at two points. to suppress radiant energyemanating from the tube.

2. A method of suppressing radiant energy emanating from a gaseousdischarge tube which consists of connecting a conductor adjacent one endof the said tube and connecting the other end of said conductor to apoint adjacent the other end of said tube at which radiant energygenerated by said tube is suppressed.

3. In combination with a gaseous discharge tube comprising an insulatinggas filled tube having a pair of electrodes, a metal clamp secured totheinsulating tube near one electrode, a secand metal clamp secured to thetube, and current conducting means connecting the two clamps, saidsecond metal clamp positioned to cause said current conduct-ing means tosuppress high frequency radiation from the tube.

4. In combination with a space discharge tube having an insulating body,and a pair of electrodes, a looped metal conductor having a pair ofterminals, and means for securing said terminals to the insulating body,said terminals being spaced from said electrodes.

5. In combination with a space discharge tube comprising a relativelylong insulating tube body having a pair of electrodes at opposite endsthereof, a pair of clamps each secured around the tube, and a loopedconductor having its ends connected to the clamps.

' 1 JAMES G. WELLS.

